2. Chemical Classification sulfate
Color clear, colorless, white, gray, yellow, red, brown
Streak white
Luster vitreous, silky, sugary
Diaphaneity transparent to translucent
Cleavage perfect
Mohs Hardness 2
Specific Gravity 2.3
Diagnostic Properties cleavage, specific gravity, low hardness
Chemical Composition hydrous calcium sulfate, CaSO4
.2H2O
Crystal System monoclinic
Uses
Use to manufacture dry wall, plaster, joint
compound. An agricultural soil treatment.
3. Chemical Classification sulfate
Color clear, colorless, white, gray, yellow, red, brown
Streak white
Luster vitreous, silky, sugary
Diaphaneity transparent to translucent
Cleavage perfect
Mohs Hardness 2
Specific Gravity 2.3
Diagnostic Properties cleavage, specific gravity, low hardness
Chemical Composition hydrous calcium sulfate, CaSO4
.2H2O
Crystal System monoclinic
Uses
Use to manufacture dry wall, plaster, joint compound.
An agricultural soil treatment.
4. Chemical Classification silicate
Color green, white, gray, brown, colorless
Streak white to pale green
Luster pearly
Diaphaneity translucent
Cleavage perfect
Mohs Hardness 1
Specific Gravity 2.7 to 2.8
Diagnostic Properties feel, color, softness, cleavage
Chemical Composition Mg3Si4O10(OH)2
Crystal System monoclinic
Uses
used as a filler and anti-stick coating in plastics,
ceramics, paint, paper, roofing, rubber, cosmetics
5. Chemical Classification halide
Color
typically purple, green and yellow. Also colorless,
blue, red and black.
Streak white
Luster vitreous
Diaphaneity transparent to translucent
Cleavage four directions of perfect cleavage
Mohs Hardness 4
Specific Gravity 3.2
Diagnostic Properties cleavage, hardness, specific gravity, color
Chemical Composition CaF2
Crystal System isometric
Uses
Numerous uses in the metallurgical, ceramics and
chemical industries. A source of fluorine, hydrofluoric
acid, metallurgical flux. High clarity pieces are used
to make lenses for microscopes, telescopes and
cameras.
6. Chemical Classification Phosphate.
Color
Green, brown, blue, yellow, violet, pink, colorless.
Transparent specimens with excellent clarity and vivid
color are used as gemstones.
Streak White.
Luster Vitreous to subresinous.
Diaphaneity Transparent to translucent.
Cleavage Poor to indistinct.
Mohs Hardness 5
Specific Gravity 3.1 to 3.3
7. Cleavage:
{001} Perfect, {010} Good
Color:
Colorless, Greenish, Grayish yellow, White, Pink.
Density:
2.56
Diaphaneity:
Transparent to translucent
Fracture:
Uneven - Flat surfaces (not cleavage) fractured in an uneven
pattern.
Hardness:
6 - Orthoclase
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
white
8. Chemical Classification silicate
Color
Quartz occurs in virtually every color. Common
colors are clear, white, gray, purple, yellow,
brown, black, pink, green, red.
Streak colorless (harder than the streak plate)
Luster vitreous
Diaphaneity transparent to translucent
Cleavage
none - typically breaks with a conchoidal
fracture
Mohs Hardness 7
Specific Gravity 2.6 to 2.7
Diagnostic Properties conchoidal fracture, glassy luster, hardness
Chemical Composition SiO2
Crystal System hexagonal
Uses
glass making, abrasive, foundry sand, hydraulic
fracturing proppant, gemstones
9. Chemical Classification silicate
Color
colorless, white, yellow, amber, pink, blue,
green, gray
Streak colorless - harder than the streak plate
Luster normally vitreous
Diaphaneity transparent to translucent
Cleavage perfect basal cleavage
Mohs Hardness 8
Specific Gravity 3.4 to 3.6
Diagnostic Properties
hardness, prismatic crystals, sometimes
striated, cleavage, specific gravity
Chemical Composition Al2SiO4(F,OH)2
Crystal System orthorhombic
Uses gemstone
10. Chemical Classification oxide
Color Typically gray to brown. Colorless when
Streak colorless (harder than the streak plate)
Luster adamantine to vitreous
Diaphaneity transparent to translucent
Cleavage
None. Corundum does display parting perpendicular to
the c-axis.
Mohs Hardness 9
Specific Gravity 3.9 to 4.1 (very high for a nonmetallic mineral)
Crystal System hexagonal
Uses
Historically used as an abrasive. Specimens with
pleasing colors have a long history of gemstone use.
11. Chemical Classification native element
Color colorless, yellow, red, orange, green, blue, and brown.
Streak
diamond is harder than a streak plate - when this
occurs the streak is called "colorless"
Luster
adamantine - the highest level of luster for a
nonmetallic mineral
Diaphaneity transparent
Cleavage perfect, octahedral
Mohs Hardness 10 - the hardest mineral
Specific Gravity 3.5 to 3.6
Uses gemstones, industrial abrasives
